function signIn () {

	var userName = document.getElementById('edit-username').value;
	var password = document.getElementById('edit-password').value;

	Class.forName('Ext.Ajax').request({
		url: $security.loginUrl,
		success: function (o) {
			var r = eval('(' + o.responseText + ')');
			if (r === true || r.success) {
				alert('您的身份认证通过，登录成功！');
				location.href = $app.context.root + "/bbs/";
			} else {
				alert('您的身份认证失败！');
			}
		},
		failure: function () {
			alert('系统故障，登录失败！');
		},
		params: {j_username:userName,j_password:password}
	});

}